Mechanism for controlling and indicating temperature limits.



Patented Sept. l9, I899. emm'ms & w. c. n. WHETHAM.

MECHANISM FOR CONTROLLING AND INDICATING TEMPERATURE LIMITS.

(No Model.)

(Application filed July 1, 1899.)

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E. H. GRIFFITHS & w. c. n. WHETHAM.

Patented Sept. 19, I899.

MECHANISM FDR CONTROLLING AND INDICATING TEMPERATURE LIMITS.

(Application filed July 1, 1899.-

(No Model.)

I I IIIIIIIIIIIII I mun I III 2 Sheets-Sheet 2 m: mums PETERS co PNOTO-LI'IHQI wnsumm'cu. n. c

UNITED STATES ERNEST IIOIVARD GRIFFITHS AND IVILLIAM CECIL DAMPIER IVIIE'II'IAM PATENT Cruise.

OF CAMBRIDGE, ENGLAND.

MECHANISM FOR CONTROLLING AND lNDlCATlNG TEMPERATURE LIMITS.

SPECIFICATION forming part of Letters Patent N 0. 633,191, dated September 19, 1899.

Application filed July 1, 1899. Serial No. 722,552. (No modelil Be it known that we, Ennns'r Ilownnn GRIFFITHS and WILLIAM OEcIL DAMPIEII \VHEIHAM, subjects of the Queen of England, residing at Cambridge, England, have invented certain new and useful Improvements in or Relating to Mechanism for Controlling and Indicating Temperature Limits, (for which we have made application for Letters Patentin Great Britain,underNo. 5,089,dated March 8, 1899,) of which the following is a specification.

This invention relates to mechanism for controlling and indicating temperature limits, and has for its object to construct a mechanism which will be capable of being readily reset after it has operated.

According to this invention a rotatable member controlled by a force is held inactive byafusible lock until a temperature has been reached which will bring about the fusing of this lock. Mechanism is provided tending to rotate this member, there being an operative connection between the driving mechanism and the member of such a nature that the apparatus can always be reset without having to renew or re-fuse the fusible look.

In applying the invention the fusible lock is formed by a small quantity of alloy metal or other suitable substance contained in a tube, one end of which is closed, the rotatable member being a rod, one end of which is immersed in the alloy in the tube. Upon the outer end of the rod may be mounted a ratchet-wheel, a star-wheel, or some other equivalent device ,which will enable the connection between some mechanism tending to rotate this rod to be reset at anytime after a temperature limit has been reached which will bring about the fusing of the alloy, this resetting device being such that no refusion or renewal of the alley or other parts of the mechanism is necessary in order to restore the apparatus to its operative state.

In the accompanying drawings, Figure l is an elevation, partly in section, showing one application of this invention for the purpose of controlling the limit of the temperature employed for heating a liquid such as milk. Fig. 2 is a perspective View of the alloy-containing tube. Fig. 3 is a sectional elevation of the invention as applied for use as an in dicator of temperature limits, as in the case of a lire-alarm. Fig. 4 is a plan of Fig. 3, the inclosingcasing of the mechanism being removed.

Like letters indicate like parts throughout the drawings.

The tube A has one end A, closed and at this closed end of the tube is placed a small quantity B of an alloy metal or other suitable substance which will fuse or become viscous or fluid at a given temperature. A rod C is placed in the tube A in such a manner that one end C will be immersed in the alloy 13, the latter forming a lock between the tube A and the rod C. Upon the outer end C of the rod C is fixed a ratchet-wheel, star-wheel, or equivalent device I).

In applying the invention to an apparatus such as is shown in Fig. 1 for heating fluids such as milk a saucepan or pot E of ordinary construction is utilized this pot having a lid F, provided with a handle F and a flange F which just flts within the top of the pot E, this lid being of the usual construction. A hole F is bored through the handle F and the part of the lid F which lies beneath the handle, the hole being of such a size as to allow the ready passage of the tube A. Attached to the top of the tube A is a strip of metal G, the ends of which are turned down, as at G, the space between the turned-down ends being approximately equal to the width of the handle F of the lid F. If new the alloy carrying lube A is passed through the hole F in the handle F and lid F and the flanges or turneddown ends G of the strip G are placed so as to lie at either side of the handle F, it will be seen that the tube will be rigidly held in relation to the lid F, which in turn will be practically rigidly connected with the pot E, owing to the friction between the flange F and the top of the pot. In this case a star-wheel D is mounted upon the up per end C of the rod C, this star-wheel being constructed, as shown in the drawings, of a disk D, provided with several radiallyprojecting fingers D In the arrangement shown in Fig. l the pot E is intended to be heated by the flame from. a gas burner or stove II of some well-known construction, the burner being provided with a cock ll for controlling the supply of gas thereto. On the spindle of this cock is rigidly mounted a bcll-cran k lever K K, the arm K of which has pivotally connected to its free end a link L, having at its free end a hook or bent finger L. The other arm K of the bell-crank lever is provided at its free end with a weight ill. The parts are so arranged that when the pot E is on the stand of the burner H the hook L on the end of the link L can be engaged with one of the fingers D of the star-wheel D, the weight M being thus held in a raised position and the gas-cock II being open. If now the contents of the pot E reach that temperature at which the alloy B in the tube A will fuse, the fusion of this alloy will release the red O, which the weight M, through the lever K K and link L and star-wheel D, is always tending to rotate. The rod C, thus released, will be rotated, when the hook L will slide off and become disengaged from the finger D of the star-wheel I), and the weight M,thus releasedavill falhthereby turning the lever K K and the cock II and shutting off the gas. As the alloy will once more become solid directly the temperature falls below the limit,t-he star-wheel D will once more be rigidly connected to the lid of the pot, and the apparatus can be reset by engaging the hook L with another finger on the star-wheel D.

If it is desired that in place of completely shutting off the gas the latter may be only partially turned off, and thus the supply of heat to the pot E merely reduced and not entirely stopped, a quadrant-plate IT may be mounted adjacent to the cock II, and by means of a pin N, which can be inserted in holes N in the plate N, the movement of the lever K K, and consequently of the cock II, can be arrested at any desired point. Of course,if preferred, the quadrant-plate N may be mounted upon the lever K K, a stop-pin being suitably arranged on the burner adjacent to the cock and in such a position that it will come in contact with the pin N on the plate N when the latter is moved.

In the construction illustrated in Figs. 3 and 4 the force tending to rotate the rotatable member 0 is that of a coiled spring. The tube A, containing the fusible lock B, is rigidly attached to a plate 0, provided with a flange or bracket 0 for enabling it to be attached to a wall or the like. The red 0 carries on its upper end a ratchet-wheel D, and pivoted either on an extension of the rod 0 or on a concentric pin is a lever P, carrying a spring-controlled pawl P, which engages with the ratchet-wheel D. A coiled spring Q is attached at one end to the plate 0 at some point 0 the other end of the spring being attached to the lever P at some point, such as P The lever P is provided with a projecting pin P for enablingit to be readily moved by the linger. The lever P is entirely or partial] y composed of insulating material and can be moved about its pivot, so as to be brought between two electric contacts R and S. The contact R consists of a metal stud in the platcO and insulated from this plate. The contactS consists of a metal spring-strip, the end of which lies over the contact-arm. The contacts 1 and S may be connected up in any electrical circuit-forexample, an electric-bell circuit; but the circuit might well include mechanism for performing some operation, such as turning on water-sprays or the like. In its normal position when set the lever P is rotated until it lies between the contacts R and S, the lever being retained in this position by the pawl P, which engages with the ratchet-wheel D, which is in turn, together with the red 0, held rigidly by the fusible lock B. It now the temperature limit is reached, the alloy 1; will fuse and the rod G, ratchet wheel D, and lever P will all be rotated by the spring Q, the removal of the insulatiug-lever P from between the contacts R and S completing the electrical circuit and ringing the alarm-bell or performing some other operation in accordance with the arrangement of the circuit. As soon, however, as the temperature falls below the limit the apparatus can be reset by merely moving the lever P about its pivot until it again lies between the contacts R and S, the pawl P passing smoothly over the teeth of the ratchet wheel D. The apparatus will now be once more held in readiness for operation, owing to the lock B having again become solid.

It is to be understood that this invention is applicable to many and various purposes, the applications above described, and illustrated in the accompanying drawings, being merely by way of example. The above-described mechanisms may obviously be modified and adapted to meet various requirements. Thus in the case of the application of the invention for use in cooking the lever controlling the gas-supply or other source of heat may be spring-controlled instead of being weighted, or the pot maybe carried upon a holder on the end of a rotatable springcontrolled or Weighted arm which will be free to turn as soon as the alloyis fused. Again, in the case of the fire-alarm the electricaleontact-coi'itrolling lever may be operated by a weight instead of by a spring.

\Ve claim- 1. I11 an apparatus for controlling and indicating temperature limits the combination. of afixed member, a relatively movablememher, a fusible lock between the fixed and movable members, mechanism tending to move the movable member and an operative connection which is between the movable memher and the mechanism tending to actuateit and is so constructed that it can be reset without necessitating renewal or refusion of the fusible lock.

2. In an apparatus for controlling and indicating temperature limits the combimttion of a fixed mcmber,arelatively movable mem- In testimony whereof we have hereto set 10 her, afusible lock between the fixed and movour hands in the presence of the subscribing able members, mechanism tending to move l witnesses.

the movable member and a ratchet-ancl-pawl T a r J x H connection which is between the movablel g fi ia member and the mechanism tending to actnate it and enables the apparatus to be reset i Witnesses:

without necessitating the renewal or refnsion HARRY GEORGE WEEKLEY,

of the fusible lock. H. O. MELTON. 

